@Adulting2021 yes, our guests came with us, the registry office was big enough.
It's unlikely you'll be able to get married at a hired house unless they have a wedding license. If they do they whole package gets very expensive. It more than doubled in costs. That's one of the reasons we kept it separate.
You can find out which venues in your area hold a wedding licence, I think this info is held by the registry office as they are the ones who would be travelling to conduct the ceremony.
The house we hired was £2,000 for three days so we had time to get the house ready. Our whole wedding came in at under £7,000 including all bridal party clothes, rings, wedding food, cake, venue, flowers for the house and bridal party, bbq's, accommodation for guests in the house and a three day wedding.
The duration was the best bit really as we had time to come together as a family with close friends and people that had travelled could stay or go as they pleased.
The house was hired as a party venue regularly so had big food prep areas and five reception rooms. It was was huge. Beautiful location and gardens for photographs.
It was a special time. Looking back the only thing I'd change is hiring more help. But everyone pitched in and it was a fun few days.